Finding location and ranging explorer

ABSTRACT

An RFID tag is used to determine the presence or absence of a user. Rules or instructions responsive to this presence or absence are implemented to control a device or multiple devices accordingly. In this manner, a device can be maintained in a normal operating mode if a user is present, even though a user is not actively interacting with the device. Moreover, the device can be shut down or locked or be on restricted access if an authorized user is no longer in the presence of the device.

FIELD OF THE INVENTION

This invention relates in general to the field of radio frequencyidentification (RFID) tags. More particularly, this invention relates tothe use of RFID tags to establish the presence of users and controldevices accordingly.

BACKGROUND OF THE INVENTION

Radio frequency identification (RFID) transponders or tags are wellknown and come in a wide variety of shapes and sizes. They can be assmall as a pencil lead in diameter and one-half inch in length. They canbe credit-card shaped for combined use with barcode visual inspectionapplications. RFID tags can also be used for inventory and securitypurposes. For example, the anti-theft hard plastic tags attached tomerchandise in stores are RFID tags.

RFID tags are categorized as either active or passive. Active RFID tagsare powered by an internal battery and are typically read/write, i.e.,tag data can be rewritten and/or modified, and typically last up to fouryears. However, active tags are less desirable in many applications dueto their cost, size, and longevity limitations.

Passive RFID tags operate without a separate external power source andobtain operating power from a reader. Passive tags are consequently muchlighter than active tags, less expensive, and offer a virtuallyunlimited operational lifetime. Read-only tags are typically passive andgenerally are programmed with a unique set of data (usually 32 to 128bits) that cannot be modified.

RFID-based designs provide for noncontact, non-line-of-sight sensing.Tags can be employed by a vendor for different purposes during theentire life-cycle of the equipment, from manufacturing to distributionto sales to deployment to services and finally disposal. Tags can beemployed by the customers for a wide range of purposes as well,including site capacity planning, asset management, and protection.

Determining an individual user's presence is vital for the growingadoption of realtime communications. Existing methods rely upon directuser interaction with an input device, such as a keyboard or mouse, todetermine a user's status, i.e., if a user is online or away from hiscomputer. Computers, devices, and other resources that may be used by anindividual or group of individuals are generally not able to recognizethe presence of a user or group of users without such directinteraction. Thus, although a user may be near his device such as acomputer, if he is not actively directly interacting with it (e.g., bypressing a key or moving a pointer) within a certain predetermined timeperiod, the device may go into a power saving mode (e.g., blank thescreen), log the user out, or otherwise prohibit the user fromimmediately accessing the system. This is undesirable if, for example,the user is present and would like the device to remain in the normaloperating mode although he is not directly interacting with it.

Similarly, in a conventional system, if a user directly interacts withthe device and then, for example, leaves the room, the device typicallyremains powered on in the regular operating mode for a predeterminedtime. This is a security concern, as another user could enter the roomand access the computer, although he may not be authorized to do so.Moreover, energy is wasted if the device remains powered on in theregular operating mode for a predetermined time after a user leaves theroom.

In view of the foregoing, there is a need for systems and methods thatovercome the limitations and drawbacks of the prior art.

SUMMARY OF THE INVENTION

The present invention is directed to the use of a radio frequencyidentification (RFID) tag to determine the presence or absence of auser. Rules or instructions responsive to this presence or absence areimplemented to control a device or multiple devices accordingly. In thismanner, a device can be maintained in a normal operating mode if a useris present, even though a user is not actively interacting with thedevice. Moreover, the device can be shut down or locked or be onrestricted access if an authorized user is no longer in the presence ofthe device.

Exemplary embodiments include an RFID tag; a detector comprising anantenna, an RF interrogator, and an RF controller; and a centralcontroller remote from the detector. The detector transmitsinterrogation signals to the RFID tag, receives and decodes presencesignals from the RFID tag, and generates instruction signals. Thecentral controller receives the instruction signals and controls atleast one associated device in accordance with the instruction signals.The device(s) being controlled can include a personal computer, atelephone, a fax machine, and a photocopier, for example.

According to aspects of the invention, the detector is disposed within akeyboard, and the central controller is disposed within a computer, withthe keyboard and the computer connected using wireless or wiredtechnologies.

According to further aspects of the invention, the range of the RFID tagrelative to the detector is determined, and the device, such as thecomputer, is controlled accordingly. Moreover, presence of multiple RFIDtags (and hence multiple users) may be determined by the detector andthe devices can be directed to operate in accordance with the individualusers' predetermined authorizations and/or preferences.

Additional features and advantages of the invention will be madeapparent from the following detailed description of illustrativeembodiments that proceeds with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary, as well as the following detailed description ofpreferred embodiments, is better understood when read in conjunctionwith the appended drawings. For the purpose of illustrating theinvention, there is shown in the drawings exemplary constructions of theinvention; however, the invention is not limited to the specific methodsand instrumentalities disclosed. In the drawings:

FIG. 1 is a block diagram of an exemplary RFID system in accordance withthe present invention;

FIG. 2 is a block diagram of an exemplary RFID system including akeyboard in accordance with the present invention;

FIG. 3 is a flow diagram of an exemplary method of determining thepresence of a user in accordance with the present invention;

FIG. 4 is a block diagram of an exemplary RFID system including sonar inaccordance with the present invention;

FIG. 5 is a flow diagram of another exemplary method of determining thepresence of a user in accordance with the present invention;

FIG. 6 is a block diagram of an exemplary RFID system including multipledevices to be controlled in accordance with the present invention;

FIG. 7 is a flow diagram of an exemplary method of controlling devicesby determining the presence of a user in accordance with the presentinvention; and

FIG. 8 is a block diagram showing an exemplary computing environment inwhich aspects of the invention may be implemented.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention determines presence using radio frequencyidentification (RFID) wireless technology, and is independent of auser's interaction with a computer. Preferably, an RFIDcontroller/reader is comprised within a keyboard used in conjunctionwith a computer.

FIG. 1 is a block diagram of an exemplary RFID system in accordance withthe present invention. An RF controller 40, which may be under controlof a central controller 60, directs an RF interrogator 35 to search forthe presence of an RFID transponder (referred to herein as an RFID tag)10 by sending signals through an antenna 30. As used herein, a detectorcomprises the antenna 30, the RF interrogator 35, and the RF controller40, for example.

More particularly, the RFID tag 10 is preferably a passive device thatdoes not require a battery and contains integrated non-volatile memorythat allows data to be written to and read from the tag. The tag can beprogrammed with the information either at installation or beforeinstallation (e.g., at a factory during manufacture). The informationthat can be programmed on the tag includes, for example, an identifier,access codes, and/or authorization codes. It is contemplated that theRFID tag 10 can be an active device, instead of a passive device. Forexample, active devices might become preferred for use in accordancewith the present invention over passive devices as, e.g., active tagcosts decline, active tag battery life is extended, active tag sizedecreases, and active tag reader/antennae form factors decrease, etc.

In accordance with the present invention, the tag 10 is used to signalthe presence of a user to the RF controller 40 (via the RF interrogator35 and the antenna 30), and ultimately the controller 60, if desired.The RF interrogator 35 generates an interrogatory signal and transmitsthis signal through the antenna 30 to the surrounding area. The antenna30 may comprise a single antenna or multiple antennae and can be anytype of appropriate antenna, such as an omnidirectional antenna.

Preferably, the RF interrogator 35 interrogates the surrounding area(via the antenna 30) for an RFID tag or tags a predetermined (andpreferably programmable) number of times per a predetermined (andpreferably programmable) period. For example, the surrounding area couldbe interrogated approximately 50 times per second. It is desirable thatthe antenna 30 and RF interrogator 35 can record a target RFID tag 10 ata range of 20 feet, though the range can be changed according to suit auser's desires. Characteristics that can be modified to affect the rangeinclude the interrogatory signal power level of the RF interrogator 35,the presence signal power level of the RFID tag 10, the detectionthreshold of the RF interrogator 30, and the characteristics of theantenna 30.

A presence signal from the RFID tag 10 is received by the antenna 30 andprovided to the RFID controller 40 via the RFID interrogator 35. Amicroprocessor (within the controller 40 or separate from the controller40) including decoder features, for example, can then act on thereceived signal to generate an appropriate output signal. This outputsignal can be provided via wired or wireless technologies to a remotecomputer (comprising central controller 60, for example), as describedin further detail below.

The RFID controller 40 preferably is able to detect multiple RFID tags,desirably simultaneously. This allows multiple users to have theirpresence established.

It is desirable to determine if a user is in the presence of a device,such as a computer, and to provide that information to a realtimeclient. The realtime client then acts on the information. In this way,if a user is in the room, but not using the laptop computer, thisinformation associated with the user's presence can be used to alert thelaptop to enter (or not enter) an appropriate mode, such as standby orsleep.

FIG. 2 is a block diagram of an exemplary RFID system including akeyboard in accordance with the present invention. FIG. 3 is a flowdiagram of an exemplary method of determining the presence of a user inaccordance with the present invention. FIG. 2 contains elements similarto those described above with respect to FIG. 1. These elements arelabeled identically are their description is omitted for brevity.

In FIG. 2, the detector, comprising the antenna 30, the RFIDinterrogator 35, and the RFID controller 40, is disposed within akeyboard 20. The keyboard 20 is connected by either wired or wirelesstechnologies to a computer, such as a personal computer (PC) 50, whichcomprises the central controller 60. For example, the keyboard 20 mighthave a USB hub and the PC 50 might have a USB port, and a USB cableconnects the keyboard 20 and the PC 50. It is contemplated that anydevice, and not only the keyboard 20, can be used to house the detector.Similarly, any device, and not only the PC 50, can be used to house thecentral controller 60. Moreover, the detector system can be disposedwithin the PC 50.

The RFID tag 10 is preferably disposed on a card or badge 5 that will bedesirably be present with the user, such as embedded in an employeeidentification badge worn by the user.

The antenna 30, which desirably resides on the keyboard 20, broadcastsinterrogating signals, at step 100. The electromagnetic field producedby the antenna 30 can be constantly present or pulsed at a giveninterval, such as every three seconds. The passive RFID tag 10associated with the user recognizes the interrogating signals andresponds with a presence signal, at step 110. The presence signalpreferably comprises data that identifies the user or tag data.According to an example, the tag data is divided into three fields, eachis 32-bit in length. The fields could be, for example, “Device ID”(user's name would be in this field), “Location Data” (mobile or fixed),and “Serial Number”. This schema can be customized.

The RFID controller 40 receives the tag data (via the antenna 30 and theRFID interrogator 35) and decodes it, if desired, at step 120. The RFIDcontroller 40 then sends the information to an optional authenticationsystem, which may reside locally or within the PC 50, for example. Then,optionally, the RFID tag is authenticated, at step 130.

It is desirable to have the antenna disposed on the keyboard or near thedesktop, because the RFID detector system can be used for other taskssuch as scanning for security purposes and/or used in conjunction withsecure login procedures. For example, the user ID could be authenticatedfor the system the user is working on. The authentication system, ifany, uses conventional authentication techniques to verify that the IDtag is authentic (e.g., has not be spoofed, and is accurate). If the tagis determined to be not authentic and hence invalid, its processingdiscontinues, and the overall process resumes at step 100.

After the tag is authenticated, or if authentication is not implementedin the system, then system control instructions associated with the tagare retrieved or otherwise determined, at step 140. More particularly,the PC 50 acts upon the information contained within the received RFIDtag data, either directly (e.g., the information contains instructions)or by accessing a storage device and looking up predetermined rules orinstructions associated with the received RFID tag data. Lookup tablesor other data storage and retrieval techniques may be implemented toassociate RFID tag data with system control instructions. The rules orinstructions are then implemented, at step 150. These rules orinstructions can be used to switch the operating mode of the PC 50, forexample. Processing continues at step 100.

The RFID controller 40 is desirably deployed in one of fourconfigurations: fixed mount, PCMCIA device, PCI card, or integrated onthe motherboard.

The distance from the RFID tag 10 to the detector (and hence thekeyboard) can also be determined. The detector, comprising the antenna30, the RF interrogator 35, and the RF controller 40, can determine therange of the RFID tag 10 by measuring the time of a returned signal fromthe RFID tag 10. Alternatively, the strength of the returned signal fromthe RFID tag 10 or its waveform shape may be used by the detector todetermine the range of the RFID tag 10. As the time, strength, orwaveform changes with each received RFID tag signal (transmitted to thedetector responsive to successive cycles of interrogating signals), itcan be determined whether the RFID tag 10, and hence the user, isapproaching the keyboard 20 or moving away from the keyboard 20.

This movement detection can be used by the central controller 60, forexample, to determine whether to activate the computer 50 (e.g.,maintain the monitor in the on state) or deactivate the computer 50(e.g., put the computer in a sleep mode, lock the computer, or turn thecomputer off) in accordance with the instructions that have beendetermined pursuant to the received tag data. Thus, the location of theuser (i.e., the RFID tag) is determined with respect to the keyboard.Preferably, this information can be used to determine the distance andbearing of the user (e.g., moving away or toward the desktop or laptop).This would allow the devices to be instructed to appropriately enterstandby or sleep or wake mode. For example, if it is determined that theuser is moving away from the keyboard, toward the door, the laptop couldenter sleep mode. If the user is moving toward the keyboard, the laptopcould awaken and be ready for usage as the user approaches the keyboard.This will save time for the user and power for the laptop.

According to an embodiment, the reader determines the user's presence bydetecting the tag on the user's ID, reading the device ID field, andcalculating the response time between when the signal is sent to the tagand received from the tag to determine relative distance and bearing,similar to sonar. Alternatively, after reading the device ID field, atag residing in a fixed location (e.g., the user's phone or monitor, aphone in a conference room) can be read, and that information providedto the PC 50 (or other computer) to triangulate the user's location.

According to a further embodiment, sonar could be used in conjunctionwith the RFID tag to determine distance and bearing of the user. Forexample, after recognizing a user with the RFID tag, then the sonar isactivated. FIG. 4 is a block diagram of an exemplary RFID systemincluding sonar in accordance with the present invention, and FIG. 5 isa flow diagram of an exemplary corresponding method. FIG. 4 containselements similar to those described above with respect to FIG. 2, andFIG. 5 contains elements similar to those described above with respectto FIG. 3. These elements are labeled identically are their descriptionis omitted for brevity.

A sonar unit 45 is desirably incorporated into the keyboard, but can beincorporated elsewhere. For example, the sonar unit can be disposed as astandalone unit, or can be incorporated into another device, such as thePC 50. After the RFID tag 10 sends its presence signal to the detector,and is authenticated at optional step 130, the RF controller 40 directsthe sonar unit 45 to activate, at step 135. At that point, the sonarunit 45 locates and tracks the RFID tag 10. The distance and bearing ofthe RFID tag 10, and thus the user, can be determined using sonartechniques.

The user distance and bearing information is desirably provided to thecentral controller 60. The central controller 60 acts on thisinformation accordingly. For example, if the central controller 60determines that the user is leaving the room, (e.g., using predeterminedrules and/or algorithms), the central controller 60 puts the computer instandby or sleep mode, or disables the computer. In this manner, anunauthorized user will not then be able to see the screen or otherwiselegitimately access the original user's data. Moreover, power savingscan be realized. The predetermined rules and/or algorithms can be storedin memory in the PC 50 that is accessible to the central controller 60.The predetermined rules and/or algorithms may also be stored in memoryassociated with the detection system (e.g., reside within the keyboard20).

The sonar can also be used to recognize when a user is approaching thekeyboard 20, and thus it can be assumed the user will be approaching touse the keyboard 20 and PC 50. In such a case, the central controller 60can recognize the approaching user and, based on stored rules, power upand/or log in the user.

When multiple devices are present or available, it would be desirable toknow which users are present and the device(s) each user is authorizedto access. For example, certain users will be authorized to use certaindevices and not others. According to an embodiment of the invention, alist of valid users and rules is maintained in storage, and these userswill be authorized to access various devices in the system, pursuant tothe rules in storage. For example, if a user is in the room, and hisRFID tag identifies him as being authorized, he will have access to usethe telephone and computer, for example. Unauthorized persons will beprevented from using these devices (i.e., locked out).

FIG. 6 is a block diagram of an exemplary RFID system including multipledevices to be controlled in accordance with the present invention, andFIG. 7 is a flow diagram of a corresponding exemplary method. FIG. 6contains elements similar to those described above with respect to FIG.2, and FIG. 7 contains elements similar to those described above withrespect to FIG. 3. These elements are labeled identically are theirdescription is omitted for brevity.

Various devices, such as a telephone 65, a fax machine 67, and aphotocopier 69, are connected to the PC 50, either through wired orwireless technologies. The stored rules or instructions associated withthe various user's tags (and thus the various users) provideauthorization to use, and activate, the various devices 65, 67, 69 ifthe user is permitted access to use these devices. The access will begranted pursuant to the tag data in the RFID tag 10 and the rules andinstructions provided to the central controller 60. After the user isauthenticated at optional step 130, the system control instructions andrules associated with the tag (and thus the user) are determined andimplemented on the local system 50 (as set forth above with respect toFIGS. 2 and 3) and on the remote systems or devices which may includedevices 65, 67, 69. In this manner, one user may be granted access to atelephone 65, but be prevented from using the fax machine 67 andphotocopier 69, while another user may have access to the fax machine 67and photocopier 69 and not be permitted to use the telephone 65. It iscontemplated that the devices 65, 67, 69 can be in the same room as theuser (and thus the RFID tag 10) and/or the PC 50 or remotely located(e.g., the user, the telephone 65, and the PC 50 are in the user'soffice, and the fax machine 67 and photocopier 69 are located in ashared printer center).

Moreover, lights and other devices in the room could be set up so thatwhen a person enters the room, his RFID tag is identified, and thedevices are put into the operating modes predetermined by a set of rulesfor that user. In other words, the desktop could control other devicessuch as telephones and lights based on user-programmed or otherpredetermined policies or rules. The policies or rules could be storedat the desktop, for example. The set of rules may be determined by theuser and/or by a central authority or administrator.

Another contemplated embodiment is directed to the handling of anincoming telephone call. If a telephone call comes in to the telephoneassociated with central controller 60 (e.g., to telephone 65), thesystem determines if the user is in the room. This determination can beperformed using the interrogation described with respect to FIGS. 2 and3, for example. If the RFID tag 10 of one authorized to use thetelephone 65 responds to the interrogation signal, then it is determinedthat an authorized user is in the room, and the call is rung through tothe telephone 65. However, if there is no response from an RFID tag 10of an authorized user to the interrogation signal, it is determined thatsuch a user is not available (e.g., is not in the room), and the call isotherwise disposed of (e.g., forwarded to a voice messaging system).

Another contemplated embodiment involves the recognition of multipleRFID tags concurrently to determine which users are in the room. Thedetector and/or the PC 50 preferably maintains a record or log of theRFID tags that are present (within range, for example) at a particulartime. This record or log can be stored in a storage device (not shown)and updated at predetermined intervals or other times. In this manner,multiple users can be tracked and can be identified when they are in aroom, for example. This would allow a teleconferencing system torecognize everyone who is in a room, entering a room, or leaving a room,for example.

It is contemplated that collisions can occur, for example, when multipleRFID tags occupy the same RF channel. Accordingly, collision detectionis preferably used to avoid or otherwise overcome the collisions betweenthe data packets or signals of the variously transmitting RFID tags. Forexample, where collisions occur, repeat transmissions are desirably useduntil all the data packets are properly received.

Although the above embodiments have been described with respect to theRFID reader (detector system) residing in a keyboard, the RFID readercan be disposed within any device, such as encapsulated within a PCMCIAdevice or integrated on a PCI card/motherboard. Alternatively, thereader could be portable, such as in a Windows CE-based portable device.

Exemplary Computing Environment

FIG. 8 illustrates an example of a suitable computing system environment800 in which the invention may be implemented. The computing systemenvironment 800 is only one example of a suitable computing environmentand is not intended to suggest any limitation as to the scope of use orfunctionality of the invention. Neither should the computing environment800 be interpreted as having any dependency or requirement relating toany one or combination of components illustrated in the exemplaryoperating environment 800.

The invention is operational with numerous other general purpose orspecial purpose computing system environments or configurations.Examples of well known computing systems, environments, and/orconfigurations that may be suitable for use with the invention include,but are not limited to, personal computers, server computers, hand-heldor laptop devices, multiprocessor systems, microprocessor-based systems,set top boxes, programmable consumer electronics, network PCs,minicomputers, mainframe computers, distributed computing environmentsthat include any of the above systems or devices, and the like.

The invention may be described in the general context ofcomputer-executable instructions, such as program modules, beingexecuted by a computer. Generally, program modules include routines,programs, objects, components, data structures, etc. that performparticular tasks or implement particular abstract data types. Theinvention may also be practiced in distributed computing environmentswhere tasks are performed by remote processing devices that are linkedthrough a communications network or other data transmission medium. In adistributed computing environment, program modules and other data may belocated in both local and remote computer storage media including memorystorage devices.

With reference to FIG. 8, an exemplary system for implementing theinvention includes a general purpose computing device in the form of acomputer 810. Components of computer 810 may include, but are notlimited to, a processing unit 820, a system memory 830, and a system bus821 that couples various system components including the system memoryto the processing unit 820. The system bus 821 may be any of severaltypes of bus structures including a memory bus or memory controller, aperipheral bus, and a local bus using any of a variety of busarchitectures. By way of example, and not limitation, such architecturesinclude Industry Standard Architecture (ISA) bus, Micro ChannelArchitecture (MCA) bus, Enhanced ISA (EISA) bus, Video ElectronicsStandards Association (VESA) local bus, and Peripheral ComponentInterconnect (PCI) bus (also known as Mezzanine bus).

Computer 810 typically includes a variety of computer readable media.Computer readable media can be any available media that can be accessedby computer 810 and includes both volatile and non-volatile media,removable and non-removable media. By way of example, and notlimitation, computer readable media may comprise computer storage mediaand communication media. Computer storage media includes both volatileand non-volatile, removable and non-removable media implemented in anymethod or technology for storage of information such as computerreadable instructions, data structures, program modules or other data.Computer storage media includes, but is not limited to, RAM, ROM,EEPROM, flash memory or other memory technology, CD-ROM, digitalversatile disks (DVD) or other optical disk storage, magnetic cassettes,magnetic tape, magnetic disk storage or other magnetic storage devices,or any other medium which can be used to store the desired informationand which can accessed by computer 810. Communication media typicallyembodies computer readable instructions, data structures, programmodules or other data in a modulated data signal such as a carrier waveor other transport mechanism and includes any information deliverymedia. The term “modulated data signal” means a signal that has one ormore of its characteristics set or changed in such a manner as to encodeinformation in the signal. By way of example, and not limitation,communication media includes wired media such as a wired network ordirect-wired connection, and wireless media such as acoustic, RF,infrared and other wireless media. Combinations of any of the aboveshould also be included within the scope of computer readable media.

The system memory 830 includes computer storage media in the form ofvolatile and/or non-volatile memory such as ROM 831 and RAM 832. A basicinput/output system 833 (BIOS), containing the basic routines that helpto transfer information between elements within computer 810, such asduring start-up, is typically stored in ROM 831. RAM 832 typicallycontains data and/or program modules that are immediately accessible toand/or presently being operated on by processing unit 820. By way ofexample, and not limitation, FIG. 8 illustrates operating system 834,application programs 835, other program modules 836, and program data837.

The computer 810 may also include other removable/non-removable,volatile/non-volatile computer storage media. By way of example only,FIG. 8 illustrates a hard disk drive 840 that reads from or writes tonon-removable, non-volatile magnetic media, a magnetic disk drive 851that reads from or writes to a removable, non-volatile magnetic disk852, and an optical disk drive 855 that reads from or writes to aremovable, non-volatile optical disk 856, such as a CD-ROM or otheroptical media. Other removable/non-removable, volatile/non-volatilecomputer storage media that can be used in the exemplary operatingenvironment include, but are not limited to, magnetic tape cassettes,flash memory cards, digital versatile disks, digital video tape, solidstate RAM, solid state ROM, and the like. The hard disk drive 841 istypically connected to the system bus 821 through a non-removable memoryinterface such as interface 840, and magnetic disk drive 851 and opticaldisk drive 855 are typically connected to the system bus 821 by aremovable memory interface, such as interface 850.

The drives and their associated computer storage media provide storageof computer readable instructions, data structures, program modules andother data for the computer 810. In FIG. 8, for example, hard disk drive841 is illustrated as storing operating system 844, application programs845, other program modules 846, and program data 847. Note that thesecomponents can either be the same as or different from operating system834, application programs 835, other program modules 836, and programdata 837. Operating system 844, application programs 845, other programmodules 846, and program data 847 are given different numbers here toillustrate that, at a minimum, they are different copies. A user mayenter commands and information into the computer 810 through inputdevices such as a keyboard 862 and pointing device 861, commonlyreferred to as a mouse, trackball or touch pad. Other input devices (notshown) may include a microphone, joystick, game pad, satellite dish,scanner, or the like. These and other input devices are often connectedto the processing unit 820 through a user input interface 860 that iscoupled to the system bus, but may be connected by other interface andbus structures, such as a parallel port, game port or a universal serialbus (USB). A monitor 891 or other type of display device is alsoconnected to the system bus 821 via an interface, such as a videointerface 890. In addition to the monitor, computers may also includeother peripheral output devices such as speakers 897 and printer 896,which may be connected through an output peripheral interface 895.

The computer 810 may operate in a networked environment using logicalconnections to one or more remote computers, such as a remote computer880. The remote computer 880 may be a personal computer, a server, arouter, a network PC, a peer device or other common network node, andtypically includes many or all of the elements described above relativeto the computer 810, although only a memory storage device 881 has beenillustrated in FIG. 8. The logical connections depicted include a LAN871 and a WAN 873, but may also include other networks. Such networkingenvironments are commonplace in offices, enterprise-wide computernetworks, intranets and the internet.

When used in a LAN networking environment, the computer 810 is connectedto the LAN 871 through a network interface or adapter 870. When used ina WAN networking environment, the computer 810 typically includes amodem 872 or other means for establishing communications over the WAN873, such as the internet. The modem 872, which may be internal orexternal, may be connected to the system bus 821 via the user inputinterface 860, or other appropriate mechanism. In a networkedenvironment, program modules depicted relative to the computer 810, orportions thereof, may be stored in the remote memory storage device. Byway of example, and not limitation, FIG. 8 illustrates remoteapplication programs 885 as residing on memory device 881. It will beappreciated that the network connections shown are exemplary and othermeans of establishing a communications link between the computers may beused.

As mentioned above, while exemplary embodiments of the present inventionhave been described in connection with various computing devices, theunderlying concepts may be applied to any computing device or system.

The various techniques described herein may be implemented in connectionwith hardware or software or, where appropriate, with a combination ofboth. Thus, the methods and apparatus of the present invention, orcertain aspects or portions thereof, may take the form of program code(i.e., instructions) embodied in tangible media, such as floppydiskettes, CD-ROMs, hard drives, or any other machine-readable storagemedium, wherein, when the program code is loaded into and executed by amachine, such as a computer, the machine becomes an apparatus forpracticing the invention. In the case of program code execution onprogrammable computers, the computing device will generally include aprocessor, a storage medium readable by the processor (includingvolatile and non-volatile memory and/or storage elements), at least oneinput device, and at least one output device. The program(s) can beimplemented in assembly or machine language, if desired. In any case,the language may be a compiled or interpreted language, and combinedwith hardware implementations.

The methods and apparatus of the present invention may also be practicedvia communications embodied in the form of program code that istransmitted over some transmission medium, such as over electricalwiring or cabling, through fiber optics, or via any other form oftransmission, wherein, when the program code is received and loaded intoand executed by a machine, such as an EPROM, a gate array, aprogrammable logic device (PLD), a client computer, or the like, themachine becomes an apparatus for practicing the invention. Whenimplemented on a general-purpose processor, the program code combineswith the processor to provide a unique apparatus that operates to invokethe functionality of the present invention. Additionally, any storagetechniques used in connection with the present invention may invariablybe a combination of hardware and software.

While the present invention has been described in connection with thepreferred embodiments of the various figures, it is to be understoodthat other similar embodiments may be used or modifications andadditions may be made to the described embodiments for performing thesame function of the present invention without deviating therefrom.Therefore, the present invention should not be limited to any singleembodiment, but rather should be construed in breadth and scope inaccordance with the appended claims.

1. A system for determining presence and providing control, comprising:a radio frequency identification (RFID) tag; a detector comprising anantenna, an RE interrogator, and an RF controller, the detector adaptedto transmit interrogation signals to the RFID tag, to receive and decodepresence signals from the RFID tag to determine whether the RFID tag isapproaching the detector or moving away from the detector, and togenerate instruction signals based on whether the RFID tag isapproaching the detector or moving away from the detector; and a centralcontroller remote from the detector and adapted to receive theinstruction signals and control at least one associated device inaccordance with the instruction signals.
 2. The system of claim 1,further comprising a card comprising the RFID tag.
 3. The system ofclaim 1, wherein the at least one device comprises a computer, and thecomputer comprises the central controller.
 4. The system of claim 3,further comprising a keyboard comprising the detector.
 5. The system ofclaim 1, wherein the central controller determines control signals basedon the received instruction signals and controls the at least one devicein accordance with the control signals.
 6. The system of claim 1,wherein the instruction signals comprise rules associated with the RFIDtag.
 7. The system of claim 1, wherein the detector determines the rangeof the RFID tag and transmits the range to the central controller, thecentral controller controlling the device based on the range.
 8. Thesystem of claim 7, wherein the central controller deactivates the deviceif the range is beyond a threshold.
 9. The system of claim 7, whereinthe central controller maintains the current operating status of thedevice if the range is less than a threshold.
 10. The system of claim 7,wherein the central controller changes the operating mode of the deviceas the range changes.
 11. The system of claim 7, wherein the centralcontroller prevents access to the device if the range is beyond athreshold.
 12. The system of claim 7, wherein the central controllerprovides login information to the device, the login informationassociated with the RFID tag, when the range is less than a thresholdand the current operating status of the device is off or if the deviceis locked.
 13. The system of claim 1, wherein the central controllermaintains the operating mode of the device based on the detection of theRFID tag.
 14. The system of claim 1, further comprising sonar fordetermining the range of the RFID tag.
 15. The system of claim 14,wherein the detector comprises the sonar.
 16. The system of claim 1,wherein the at least one device comprises at least one of a telephone, afax machine, and a photocopier.
 17. The system of claim 1, wherein thedetector is adapted to receive presence signals from a plurality of RFIDtags, and the central controller controls the at least one device inaccordance with the information received from the RFID tags.
 18. Amethod for determining presence and providing control, comprising:receiving a presence signal from at least one radio frequencyidentification (RFID) tag at a detector comprising an RF controller;determining whether the RFID tag is approaching the detector or movingaway from the detector based on the presence signal; generating anoutput signal in response to the presence signal and whether the RFIDtag is approaching the detector or moving away from the detector;providing the output signal to a remote central controller; andcontrolling at least one device, via the remote central controller,based on the output signal.
 19. The method of claim 18, furthercomprising searching for the presence of the RFID tag by transmitting aninterrogating signal at predetermined intervals.
 20. The method of claim18, further comprising receiving a plurality of presence signals, eachsignal associated with a different one of a plurality of RFID tags, andcontrolling the at least one device in accordance with the informationreceived from the RFID tags.
 21. The method of claim 18, furthercomprising decoding the presence signal prior and generating the outputsignal based on the decoded presence signal.
 22. The method of claim 18,wherein the output signal comprises instructions and rules for theremote controller to implement on the at least one device.
 23. Themethod of claim 18, further comprising determining the range of the RFIDtag.
 24. The method of claim 23, wherein determining the range comprisesusing sonar to determine the range.
 25. The method of claim 23, furthercomprising changing the operating mode of the at least one device basedon the range of the RFID tag.
 26. The method of claim 25, whereinchanging the operating mode comprises preventing access to the device ofthe range is beyond a threshold.
 27. The method of claim 25, whereinchanging the operating mode comprises deactivating the device if therange is beyond a threshold.
 28. The method of claim 25, whereinchanging the operating mode comprises maintaining the current operatingstatus of the device is the range is less than a threshold.
 29. Themethod of claim 18, further comprising embedding the RFID tag into aportable card, and disposing the detector in a keyboard.
 30. The methodof claim 18, further comprising providing information to the device, thelogin information associated with the RFID tag, when the range is lessthan a threshold and the current operating status of the device is offor if the device is locked.
 31. The method of claim 18, wherein the atleast one device comprises at least one of a computer, a telephone, afax machine, and a photocopier.